Air-depolarized cell



NOV 15, 1955 c. R. FISHER ETAL AIR-DEPOLARIZED CELL Filed Sept. 21, 1953 ATTORNEY United States Patent O AIR-DEPLARIZED CELL Application September 21, 1953, Serial No. 381,388 7 Claims. (Cl. 13G-102) Fremont,

This invention relates to an air-depolarized cell and,

more particularly, to a railway signal cell of the air-depolarized type.

Air-depolarized cells have proved to be particularly useful in connection with the operation of railway signal lights and similar equipment. Dependability under variable weather conditions and a relatively long life are attributes much to be desired in a cell to be used with such devices. This is true because cells having a short life require frequent servicing and those which operate improperly or unpredictably under a wide range of temperatures cannot be relied on.

It is the object of the present invention to provide a cell having a relatively long life. Another object is to provide a cell capable of withstanding a continuous drain of current for a long period of time. It is a further object of the invention to provide a cell which has im-` proved operating characteristics over a Wide range of temperatures and exceptionally good performance at low temperatures. The objects are accomplished by the signal cell shown in the accompanying drawing.

In the drawing:

Fig. 1 is a perspective View of a railway signal cell; Fig. 2 is a perspective view, parts being broken away, of a replaceable anode and cathode unit;

Fig. 3 is a sectional view taken along the line 3-3 of the unit shown in Fig. 2;

Fig. 4 is a sectional View taken along the line 4-4 of the unit shown in Fig. 2; and

Fig. 5 is a sectional View taken along the line 5-5 of the unit shown in Fig. 3.

In the railway signal cell of the invention a container 11, suitably of glass or plastic, is provided with a replaceable anode and cathode unit 12 which is attached, as by a bolt 13, to the cover 14 of the container 11. The cover and container are preferably those specilied as standard for 500 ampere hour cells by the American Association of Railroads. The replaceable unit 12 comprises zinc anodes 15 and a carbon cathode 16. An electrolyte is placed in the `container 11 and the unit 12 suspended from the cover 14 of the container 11 so that the anodes 15 and cathode 16 are substantially submerged in the electrolyte. Channels or other hollow spaces extending from the top downward into the cathode 16 provide for the air depolarization of the cell. The cathode is made impermeable to liquids to prevent the lilling of the channels or hollow spaces with electrolyte. The replaceable unit 12 may be discarded when the zinc anodes 15 have been consumed or a new unit rebuilt on the frame of the old.

In the preferred replaceable cathode and anode unit 21 shown in Fig. 2, zinc plates 22 are mounted on either side of a cathode unit 23. The cathode unit 23 comprises two perforated steel panels 24 onto which a carbon composition 25 has been secured. A frame 26 extends around three sides of the steel panels 24 and the carbon composition 25 secured thereon, holding the two panels 24 apart. This frame sealngly engages the three 2,724,010 Patented Nov. 15, 1955 cer sides of the steel panels 24 and the carbon composition 25. The frame 26 is open on the fourth or top side to provide access from the air to the space between the steel panels 24.

The frame 26 is provided near the top or open side with projections 27. An annular opening passing through these projections 27 permits the suspension of the zinc plates 22 from the frame 26 by means of a bolt 28 passing through the projections and the zinc plates 22. Suitably, the bolt is held in the annular opening by the nut 29. Preferably, the annular opening extends through the steel panels 24 and the carbon composition 25. The zinc plates 22 are positioned one on either side of the frame 26 containing the steel panels 24 and carbon composition 25. A wire 31 in electrical contact with the bolt 2 serves as one terminal of the cell.

As best seen in Fig. 3, the steel panels 24 extend above the zinc plates and carbon composition into the open end of the frame 26. The extended portions of the panels 24 are in electrical contact with a terminal member 32. The terminal member 32 comprises, for example, a bolt 33 passing through the extended portions of the plates and secured in place by a nut 34 and washers 35. Preferably, a brace 36 extends across the open end of the frame 26 to strengthen this member.

The carbon composition used in the cell of the invention is a plastic bonded material which may easily be molded into shape and attached to the panels 24. To fabricate a carbon covered panel such as is used in the cell of the invention, an air-depolarizable granular carbon is blended with polymerizable material. The polymerizable material is rendered plastic, suitably by the use of a plasticizer, and after the carbon composition has been applied to the steel plate the plasticizer or other softening iniluence is removed permitting the composition to harden in contact with the panel.

In a preferred embodiment of the invention, the carbon used is a granular activated charcoal. This activated carbon is mixed with a resin, suitably a vinyl resin and a plasticizer. The plasticizer causes the vinyl resin to become sticky and pliant. When this composition is applied to the steel panels and the plasticizer removed, as by heating, the carbon composition adheres tightly to the panel. To enhance the adhesion of the carbon composition, the panel may be etched slightly with an acid and coated with a resin compatible with the resin in the carbon composition. With the materials described herein this coating can be advantageously of a vinyl resin.

Since the carbon in the cell must be water-impermeable to insure the proper action of the cell, a waterprooiing treatment must be given to the carbon composition. A preferred treatment comprises mixing with the carbon and resin, prior to the molding on the steel panel, Waterproofing agents, suitably petroleum oils and rubber cements, i. e. a solution of rubber in toluol. The incorporation in the carbon composition of a small quantity of acetylene black has also been found to impart a desirable water-repellency to the carbon composition.

The carbon composition and the steel panel which has been joined as described above are secured in the frame with a resinous cement. Again care should be taken to see that the cement used is compatible with both the plastic material in the carbon composition and the material of which the frame is constructed. Good results` have been obtained with a polystyrene frame and a cement consisting predominantly of a vinyl resin.

The preferred unit of the invention is provided with a divider 41, as best shown in Fig. 4, which divides the space between the steel panels into two separate compartments. This divider in the preferred arrangement is a plastic strip extending upward from the bottom to the open end of the frame and made integral with the frame. Should one section of vthe air space become ooded with `electrolyte, water or other similar materials, the divider permits the continued operation of the cell at a somewhat reduced etliciency, but nevertheless prevents the total failure of the cell.

The electrolyte used in the cell of the invention may be an aqueous solution of sodium hydroxide. For best results at low temperatures an electrolyte of potassium hydroxide is preferred.

It will be understood that other provisions may be made in the construction of the cell for'the access of air to the carbon cathode. This may be done, for example, by providing a solid carbon block of the composition described above in which the steel panels are embedded and extending holes into the carbon block from the top side so as to provide for the circulation of air in the block. While best results have been obtained with the arrangement shown in Figs. 2 to 5, which permits the maximum contact between air and the cathode, good results may be obtained with less than this maximum contact.

'What is claimed is:

l. An anode and cathode unit for an air-depolarized cell comprising a pair of metallic panels spaced apart to form a channel therebetween, a carbon electrode bonded Y to and in electrical contact with each of said panels, each of said electrodes being positioned on a side of a panel opposite said channel a portion of each of said electrodes being exposed to said channel, said electrodes being liquid-impermeable, a frame supporting said panels and electrodes and extending around the periphery of said panels and electrodes enclosing said channel on all butV one side which side o pens on a passage through said frame, said panels extending into said passage and being electrically connected to a terminal, a pair of zinc plates each substantially parallel to and spaced from that side of an electrode most distant from said channel, said zinc plates being supported by said frame and electrically connected to a terminal.

2. An anode and cathode unit for an air-depolarized cell comprising a pair of metallic panels spaced apart to form a channel therebetween, a carbon electrode bonded to and in electrical contact with each of said panels, each of said carbon electrodes comprising granular, air-depolarizable carbon bonded together with a resin, each of said electrodes being positioned on a side of a panel opposite said channel a portion of each of said electrodes being exposed to said channel, said electrodes being liquid-impermeable, a frame supporting said panels and electrodes and extending around the periphery of said panels and electrodes enclosing said channel on all but one side which side opens on a passage through said frame, said panels extending into said passage and being electrically connected .to a terminal, a pair of zinc plates each-substantially parallel to and spaced from that side of an electrode mosty distant from said channel, said zinc plates being supported by said frame and electrically connected to a terminal.

3. An ranode and cathode unit for an air-depolarized cell comprising a pair of metallic panels spaced apart to form a channel therebetween, a carbon electrode bonded to and in electrical contact with each of said panels, each of said carbon electrodes comprising granular, air-depolarizable carbon bonded together with a vinyl resin, each of said electrodes being positioned on a side of a panel opposite said channel a portion of each of said electrodes being exposed to said channel, said electrodes being liquid-impermeable, a frame supporting said panels andelectrodes and extending around the periphery of said panels and electrodes enclosing said channel on all but one side which side opens on a passage frame, said panels extending into said passage andV being electrically connected to a terminaba pair of zinc plates each substantially parallel to and spaced from that side of an electrode Amost distant from said channel, said zinc through said 4 plates being supported by said frame and electrically connected `to a terminal. Y

4. vAn anode and cathode unit for an air-depolarized cell comprising a pair of perforated metallic panels spaced apart to form a channel therebetween, a carbon electrode bonded to and in electrical contact with each of said panels, each of said carbon electrodes comprising granular, ar-depolarizable carbon bonded together with a vinyl resin, each of said electrodes being positioned on a side of a panel Vopposite said channel a portion of each of said electrodes being exposed to said channel, said electrodes being liquid-impermeable, a frame supporting said panels and electrodes and extending around the periphery of said panels and electrodes enclosing said channel on all but one side which side opens on a passage through said frame, said panels extending into said passage and being electrically connected to a terminal, a pair of zinc plates each substantially parallel to and spaced from that side of an electrode most distant from said channel, said zinc plates being supported by said frame and electrically connected to a terminal.

5. An anode and cathode unit for an air-depolarized cell comprising a pair of metallic panels spaced apart to form a -channel therebetween, a carbon electrode bonded to and in electrical contact with each of said panels, each of said carbon electrodes comprising granular, airdepolarizable carbon bonded together with a resin, each of said electrodes being positioned on a side of a panel opposite said channel a portion of each of said electrodes being exposed to said channel, said electrodes being liquid-impermeable, a unitary frame supporting said panels and electrodes and extending around the periphery of saidrpanels and electrodes enclosing said channel on all but one side which side opens en a passage through .said frame, said panels extending into said passage and being electrically connected to a terminal, a pair of zinc plates each substantially parallel to and spaced from that side of an electrode most distant from said channel, said Zinc plates being supported by said frame and electrically connected to a terminal.

6. An anode andy cathode unit for an air-depolarized cell comprising a pair of metallic panels spaced apart to form a channel therebetween7 a carbon eiectrode bonded to and in electrical contact with each of said panels, each of said electrodes being positioned on a side of a panel opposite said channel, a portion of each of said electrodes being exposed to said channel, said electrodes being liquidimpermeable, a frame supporting said panels and electrodes and extending around the periphery of said panels and electrodes enclosing said channel on all but one side which side opens on a passage through said frame, said panels extending into said passage and being electrically connected to a terminal, said frame delininga second opening passing through said frame at substantially right angles to said carbon electrodes through said channel and sealed therefrom, a pair of zinc plates each substantially parallel to and spaced from that side of an electrode most distant from said channel, said'zinc plates supported'and electrically connected by a conductive member extending from one plate through said passage to the other plate,

cell comprising a pair of metallic panels spaced apart to form a channel therebetween, a carbon electrode bonded to and in electrical contact with each of said panels,

each of said electrodes being positioned on aside of a panel opposite said channel, a portion of each of said electrodes being exposed to said channel, said electrodes being liquid-impermeable, a frame supporting said panels and electrodes and extending around the periphery of said panels and electrodes enclosing said channel on all but one side which side opens on a passage through said y frame, a member extending from said passage to a position on said frame opposite said passage, said member sealingly engaging said panels Yand said frame thereby 5 6 dividing said channel into a plurality of independent References Cited in the file of this patent compartments, said panels extending into said passage and UNITED STATES PATENTS being electrically connected to a terminal, a pair of zinc 2 048 804 I J l 8 1936 plates each substantially parallel to and spaced from 25729 18 llgseta Olty go 1951 that side of an electrode most distant from said channel, 5 2,597,116 Marsal et al May 20 1952 said zinc plates being supported by said frame and electrically connected to a terminal. 

1. AN ANODE AND CATHODE UNIT FOR AN AIR-DEPOLARIZED CELL COMPRISING A PAIR OF METALLIC PANELS SPACED APART TO FORM A CHANNEL THEREBETWEEN, A CARBON ELECTRODE BONDED TO AND IN ELECTRICAL CONTACT WITH EACH OF SAID PANELS, EACH OF SAID ELECTRODES BEING POSITIONED ON A SIDE OF A PANEL OPPOSITE SAID CHANNEL A PORTION OF EACH OF SAID ELECTRODES BEING EXPOSED TO SAID CHANNEL, SAID ELECTRODES BEING LIQUID-IMPERMEABLE, A FRAME SUPPORTING SAID PANELS AND ELECTRODES AND EXTENDING AROUND THE PERIPHERY OF SAID PANELS AND ELECTRODES ENCLOSING SAID CHANNEL ON ALL BUT ONE SIDE WHICH SIDE OPENS ON A PASSAGE THROUGH SAID FRAME, SAID PANELS EXTENDING INTO SAID PASSAGE AND BEING ELECTRICALLY CONNECTED TO A TERMINAL, A PAIR OF ZINC PLATES EACH SUBSTANTIALLY PARALLEL TO AND SPACED FROM THAT SIDE OF AN ELECTRODE MOST DISTANT FROM SAID CHANNEL, SAID ZINC PLATES BEING SUPPORTED BY SAID FRAME AND ELECTRICALLY CONNECTED TO A TERMINAL. 